1. Field of Invention
The invention relates generally to a device for perforating a wellbore. More specifically, the present invention relates to a charge device having a perforating bullet equipped with energetic material.
2. Description of Prior Art
Perforating systems are used for the purpose, among others, of making hydraulic communication passages, called perforations, in wellbores drilled through earth formations so that predetermined zones of the earth formations can be hydraulically connected to the wellbore. Perforations are needed because wellbores are typically completed by coaxially inserting a pipe or casing into the wellbore. The casing is retained in the wellbore by pumping cement into the annular space between the wellbore and the casing. The cemented casing is provided in the wellbore for the specific purpose of hydraulically isolating from each other the various earth formations penetrated by the wellbore.
Perforating systems typically include one or more perforating guns connected together in series to form a perforating gun string, which can sometimes surpass a thousand feet of perforating length. The gun strings are usually lowered into a wellbore on a wireline, where the individual perforating guns are generally coupled together by connector subs. Often, a surface truck accompanies the perforating systems that connects to an upper end of the wireline. In addition to being used for raising and lowering the gun string, the wireline typically is used as a communication means and control signal path between the truck and the perforating string. The wireline is generally threaded through pulleys supported above the wellbore. Derricks, slips and other similar systems may sometimes be used in lieu of a surface truck for inserting and retrieving the perforating system into and from a wellbore. Also, tubing, drill pipe, slick line, and/or coiled tubing are alternatives to wireline for disposing perforating systems into a wellbore.